The day before he begins attending high school, Ashiya Hanae becomes possessed by a strange fuzzy yokai. Being possessed causes him to fall ill, and while spending the start of his high school life repeatedly making trips to the nurse's office, he comes across the contact information of the Mononokean, which specializes in exorcising yokai, and decides to call them. When Ashiya finally visits the Mononokean, he meets the morose master Abeno Haruitsuki.

After making friends with his classmates Saga and Fushimi, Ashiya believes the high school life he dreamed of may finally be his. But before he has the chance to enjoy his new life, he's instructed to go to a certain temple alone to find and return a yokai's lost possession. At the temple, Ashiya meets a girl named Fujiwara Zenko, and it seems the lost possession in question has something to do with Zenko's father, the head priest.